Longhorn Block Storage

Hello everybody! 🫡

Today I'm going to tell you about Longhorn Block Storage. First of all, what is Longhorn? What is it for? Why is it used? Let's find out... 💪

Longhorn is a lightweight, reliable, and easy-to-use distributed block storage system for Kubernetes.

Longhorn is free, open-source software. Originally developed by Rancher Labs, it is now being developed as an incubating project of the Cloud Native Computing Foundation.

With Longhorn, you can:

  • Use Longhorn volumes as persistent storage for the distributed stateful applications in your Kubernetes cluster
  • Partition your block storage into Longhorn volumes so that you can use Kubernetes volumes with or without a cloud provider
  • Replicate block storage across multiple nodes and data centers to increase availability
  • Store backup data in external storage such as NFS or AWS S3
  • Create cross-cluster disaster recovery volumes so that data from a primary Kubernetes cluster can be quickly recovered from backup in a second Kubernetes cluster
  • Schedule recurring snapshots of a volume, and schedule recurring backups to NFS or S3-compatible secondary storage
  • Restore volumes from backup
  • Upgrade Longhorn without disrupting persistent volumes

So what have we learned about Longhorn so far? Now let's see how we install K8s on it.

📌 First of all, we need to set up the helm in our cluster.

Okay, let's go on now.

Now let's add Longhorn to the helm repository and update our repom. 

helm repo add longhorn https://charts.longhorn.io 
Helm repo update

If we get here smoothly, we can go on.

Next, we have to set up the Longhorn. Let's create a new namespace and install Longhorn. 👇

kubectl create namespace longhorn-system helm install longhorn longhorn/longhorn --namespace longhorn-system

Installation finished ✅

How easy it was, wasn't it? It would be nice to see Longhorn as the UI at once,is it? Let's do that.

kubectl get service -n longhorn-system

Let's list longhorn-frontend with the command above. And with the command below, let's get this service port-forward.

kubectl port-forward -n longhorn-system service/longhorn-frontend 8080:80

Now visit localhost:8080 and enjoy longhorn.

We need to test the last Longhorn that we set up, right?

helm install my-release oci://registry-1.docker.io/bitnamicharts/mysql

Let's use the following command to display bitnamicharts/mysql PersistentVolume, PersistentVolumeClaim and the Longhorn StorageClass that we have installed.

kubectl get pv,pvc -n default
kubectl get storageclass -n default

In fact, the Longhorn installation is so simple. See you on the next blog. 🎈